Problems of public health are highly interdisciplinary. Their solution depends upon the understanding of phenomena in mammals exposed to a variety of "insults," e.g., by radiation or by countless noxious chemicals. Information of this kind is or can be available from controlled experiments on animals, like mice, rats, dogs, etc. Here the basic scientific fields are biology, chemistry, physics and, yes, probability and statistics, particularly the design of experiments and their evaluation. However, the problems of public health are broader. Human societies differ substantially from populations of mammals studied in controlled experiments. Human societies are composed of individuals who differ from each other in many respects: genetics, differences in socio-economic status and a tremendous variability of patterns of environmental conditions. The proposed work is to continue the studies of the Statistical Laboratory, conducted for many years now. It includes: (1) the chance mechanisms that operate in populations of single cells in living organisms subjected to the different insults; (2) the chance mechanisms operating in living mammals each composed of a number of different tissues; (3) the design and evaluation of relevant experiments that are in a defined sense "optimal," and (4) the complex domain that may be symbolized by the term "energy crisis, pollution and public health".